Field of the Invention
The present invention relates to an arrangement for recognizing obstacles such as, for example, overhead lines, wire cables, pylons and the like, for pilots of low-flying aircraft, particularly helicopters, comprising a pulsed laser range finder composed of a transmitter and a receiver for scanning a field of view and for the pictorial display of the course of the recognized obstacle.
A basic arrangement of this type is disclosed in the German published application 24 02 537.
Low-flying aircraft such as, for example, helicopters, being used for close ground support are jeopardized for obstacles such as, for example, overhead lines, wire cables of cable ways, pylons and the like, that hardly be perceived by a pilot, particularly at night or given poor visibility conditions. Warning devices that operate according to the laser radar principle have already been proposed for recognizing such obstacles. In the arrangement disclosed in the aforementioned German published application 24 02 537, the scanning of the terrain of interest occurs in concentric circles or helically with a laser beam of a pulsed laser range finder composed of a transmitter and a receiver. The course of the recognized obstacle is portrayed, with respect to the helicopter, for example, on a picture screen. Scanning a given field of view with a single laser beam, however, requires a relatively-great amount of time. Moreover, involved components such as, for example, a laser having a high pulse repetition frequency and a complicated scanner mechanism having a high scan mirror frequency in azimuth and elevation are required for this purpose. This equipment expense has an unbeneficial influence on the size and weight of the arrangement.